Cheek and lip expansion device and method

ABSTRACT

Cheek and lip expansion devices including an upper frame portion configured to extend about an upper dental arch, and a lower frame portion configured to extend about a lower dental arch. The upper and lower frame portions may each include first and second side members, each with anterior and posterior regions. An upper connecting member may extend between the anterior regions of the upper side members. A lower connecting member may extend between the anterior regions of the lower side members. The posterior regions of the upper and lower side members on respective sides of the frame are joined to one another to form a bendable radius that resists bending at a distinct point. The bendable radius on opposed sides permits the frame to be collapsed top to bottom. The frame may be collapsible side-to-side. A posterior crossbar may be provided extending between the posterior regions of the side members.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 14/858,954, filed Sep. 18, 2015 entitled CHEEK AND LIPEXPANSION DEVICE AND METHOD, which is a continuation-in-part of U.S.patent application Ser. No. 14/776,867, filed Sep. 15, 2015, entitledCHEEK RETRACTOR DEVICE AND METHOD”, which is a 35 U.S.C § 371 nationalstage application of PCT Application PCT/US14/28083, filed Mar. 14,2014, entitled CHEEK RETRACTOR DEVICE AND METHOD” which claims thebenefit of U.S. Provisional Patent Application Ser. No. 61/789,929,filed Mar. 15, 2013, entitled “CHEEK RETRACTOR DEVICE AND METHOD”. Thedisclosure of each of the foregoing is incorporated by reference in itsentirety.

BACKGROUND 1. The Field of the Invention

The present invention is in the field of dentistry, particularly devicesfor isolating a patient's teeth from soft oral tissue and enlarging theworking field for the practitioner.

2. The Relevant Technology

In certain procedures, particularly certain dental procedures, it can behelpful to retract soft oral tissue of the oral cavity from a patient'steeth so as to create an enlarged working field around the teeth anddental arches. Various retraction devices exist, although these devicesshare certain problems. They are often difficult to insert and remove,often requiring extensive time to insert and causing discomfort to thepatient during insertion and removal. They generally require that adentist, dental assistant, or other practitioner use both hands toinsert and remove the devices. They are generally uncomfortable topatients and can activate patient's pharyngeal reflexes (i.e., gagreflex).

In some cases they simply stretch the lips apart without directlybearing against the cheeks. In such cases, they do not permit furthermanipulation of the patient's lips or cheeks without causing pain. Inother cases, they include bulky lip retraction structures that can blockaccess to tooth surfaces along the sides of a dental arch. In stillother cases, they are formed from rigid wires bent into a clam-shellstructure that have little flexibility and which can exert significantpressure onto sensitive oral tissue, such as the sulcus between thegingiva and lips.

As such, it would be beneficial to provide a cheek and lip retraction orexpansion device exhibiting improved characteristics.

BRIEF SUMMARY

Disclosed herein are cheek and lip retraction or expansion devices foruse in dental procedures or other procedures requiring access to theoral cavity with minimal obstruction. Various features are disclosedwhich may provide collapsibility, ability to latch in a collapsedconfiguration, and easier insertion into a patient's mouth, (e.g., evenallowing insertion with one hand). The device may include structuraland/or curvature characteristics which help “pull” the device into apatient's mouth, facilitating easier insertion and maintenance withinthe mouth once installed.

In an aspect, the cheek and lip retraction or expansion device includesa frame that is flexible and resilient so as to be selectivelycollapsible and expandable to facilitate insertion into the mouth whenin collapsed configuration and retraction or displacement of a person'scheeks and lips from teeth of the upper and lower dental arches when inan expanded configuration. The expanded frame can comfortably bearagainst and inflate, displace, and/or flare outward the cheeks and lipsto provide an opening effect (e.g., an umbrella- or tent-like effect).As used herein, the device may be interchangeably described as aretraction or expansion device. It will be appreciated that the devicemay tend to expand the cheeks and lips outward and forward (away fromthe dental arch and other surfaces they normally rest against), withoutuncomfortably retracting (really stretching) the lips side-to-side,which is what is accomplished by many existing devices.

The frame includes an upper frame portion configured to extend about aperson's upper dental arch, so as to bear against and retract soft oraltissue (e.g., cheeks and upper lip) from one or more teeth of the upperdental arch when the frame is in an expanded configuration. The framealso includes a lower frame portion configured to extend about aperson's lower dental arch, so as to bear against and retract soft oraltissue (e.g., cheeks and upper lip) from one or more teeth of the lowerdental arch when the frame is in an expanded configuration. The upperframe portion includes first and second upper side members, each upperside member including a posterior region and an anterior region. Anupper anterior connecting member is positioned between the anteriorregions of the first and second upper side members. The lower frameportion similarly includes first and second lower side members, eachlower side member including a posterior region and an anterior region. Alower anterior connecting member is positioned between the anteriorregions of the first and second lower side members.

The upper side members of the upper frame portion are joined tocorresponding lower side members of the lower frame portion at theirposterior regions. For example, the first upper and lower side memberscan be joined on a left side of the frame, and the second upper andlower side members can be joined on a right side of the frame. In someembodiments, the upper and lower side members form a bendable radius ina posterior region of the frame that resists bending at a distinct pointso as to create a larger bending radius where the bending moment isspread over a greater length along the upper and lower side members. Thefirst upper and lower side members joined at their posterior regionsform a first posterior arced region or joint (e.g., on the left side ofthe frame). The second upper and lower side members are similarly joinedat their posterior regions to form a second posterior arced region orjoint (e.g., on the right side of the frame). In some embodiments, theposterior regions of the side members can be thickened in the vicinityof the first and second posterior joints so as to resist bending atdistinct points, resulting in bendable radii that spread bending forcesout anteriorly towards the anterior ends of the respective side members.In another embodiment, mechanisms other than thickening could beemployed to also resist bending (e.g., use of a different material,etc.) Such a configuration permits the upper and lower frame portions tobe at least partially collapsed or folded top to bottom, toward eachother.

The frame also has a posterior width (e.g., between the first and secondposterior joints) that is greater than either or both of the upper andlower anterior width dimensions. Such a configuration of greaterposterior width than anterior widths helps to pull the device into themouth, rather than push it out. By comparison, other cheek or lipretractors exhibit an oppositely configured wedge relationship where theanterior dimensions of the device are greater than the posteriordimensions. Such configurations exhibit a tendency to be easily pushedout of the oral cavity, rather than maintained in the desired position.In addition, they tend to stretch the lips to their greatest possibleside-to-side extent, which is both uncomfortable for the patient andunhelpful to the practitioner, as it does not permit the practitionerany additional flexibility to pull one side of the lip (or both sides)to further expand the view and/or working field.

In some embodiments, the frame may further comprise a posterior crossbarpositioned between (e.g., interconnecting) first and second posteriorregions of the upper and lower frame portions. In some embodiments, theposterior crossbar interconnects the first and second posterior jointsbetween the first and second upper and lower side members, respectively.The posterior crossbar is advantageously flexible and resilient topermit selective side-to-side collapse and expansion of the frame. Inthis way, the posterior crossbar can assist in providing an expansionforce (e.g., in the x-axis direction) to the posterior arced regions ofthe upper and lower frame portions in order to retract cheeks from apatient's dental arches, particularly in the posterior region of thepatient's mouth. The posterior crossbar may include first and secondmembers having a posterior curvature, being joined at essentially amiddle portion of the crossbar to create one or more preferentialbending regions. The posterior crossbar can be configured and positionedso as to lie behind a person's posterior-most teeth (e.g., second molarsin the case of an adult). In this configuration, the posterior crossbardoes not extend and form a bridge across a patient's posterior teeth,which can otherwise obstruct and interfere with the ability of thepatient to bite down and join occlusal surfaces of upper and lowerposterior teeth. The posterior crossbar can also assist in retracting orexpanding the patients lips forward (e.g., anteriorly in the z-axisdirection) and outwardly from anterior teeth (e.g., incisors andcuspids). It does this by interacting with (e.g., at least partiallyabutting posterior soft oral tissue associated with the mandibularramus) to create posterior loading of the flexible spring-like frame toassist in flaring the cheeks and lips outwardly and away from adjacentposterior and anterior teeth of the upper and lower dental arches.

In some embodiments, where a posterior crossbar is provided, aselectively removable tongue guard may be provided that is selectivelycoupleable to the crossbar, to allow selective attachment or removal ofthe tongue guard, even with the device expanded, in the mouth.

In some embodiments, the upper frame portion can have an anterior widththat is greater than an anterior width of the lower frame portion. Forexample, the upper anterior connecting member between the first andsecond upper side members can have a length that is greater than thelength of the lower anterior connecting member between the first andsecond lower side members. This can help accommodate differences betweenthe size and anatomy of the upper and lower dental arches, and theassociated vestibules between the dental arch and the cheek and/or lipsinto which the upper and lower frame portions are placed when the frameis expanded. For example, such a difference in upper and lower anteriorwidths better accommodates the anatomy into which the frame is placed,where the upper dental arch (and the associated upper anteriorvestibule) is typically wider than the lower dental arch (and associatedlower anterior vestibule).

In some embodiments, the cheek and lip retraction or expansion devicemay include an upper lip protecting member disposed on or forming partof the upper anterior connecting member of the upper frame portion andthat is configured to extend away from an oral cavity and over an upperlip. A lower lip protecting member may similarly be disposed on or formpart of the lower anterior connecting member of the lower frame portionin a manner to extend away from the oral cavity and over a lower lip. Insome embodiments, the lip protecting members may be selectivelyengagable with one another (e.g., corresponding latching structure maybe provided on each) when the upper frame portion is folded towards thelower frame portion so as to temporarily latch the upper and lower frameportions together. This can aid the practitioner and facilitateinsertion of the retraction or expansion device using one hand. Forexample, latching the upper and lower members can free up a hand thatmight otherwise be required to collapse the upper and lower memberstogether (e.g., in the y-axis direction) while using one hand tocollapse the frame from side-to-side (e.g., in the x-axis direction).

These and other benefits, advantages and features of the presentinvention will become more fully apparent from the following descriptionand appended claims, or may be learned by the practice of the inventionas set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of thepresent invention, a more particular description of the invention willbe rendered by references to specific embodiments thereof, which areillustrated in the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 is an anterior view of an exemplary expanded cheek and lipexpansion device.

FIG. 2 is a front perspective view of the cheek and lip expansion deviceof FIG. 1.

FIG. 3 is a side view of the cheek and lip expansion device of FIG. 1,with the upper frame portion also shown in broken lines indicating howit may be folded and latched with the lower frame portion.

FIG. 4 is a posterior or rear perspective view of the cheek and lipexpansion device of FIG. 1.

FIG. 5 is an anterior or front view of the cheek and lip expansiondevice of FIG. 1 installed within the oral cavity of a patient.

FIG. 6 is an anterior or front view of an alternative exemplary expandedcheek and lip expansion device.

FIG. 7 is a front perspective view of the cheek and lip expansion deviceof FIG. 6.

FIG. 8 is a side view of the cheek and lip expansion device of FIG. 6,with the upper frame portion also shown in broken lines indicating howit may be folded and latched with the lower frame portion.

FIG. 9 is a posterior or rear perspective view of the cheek and lipexpansion device of FIG. 6.

FIG. 10A is an anterior or front view of the cheek and lip expansiondevice of FIG. 6 installed within the oral cavity of a patient.

FIG. 10B-10C are side profile views showing the patient's mouth withoutthe expansion device installed (FIG. 10B) and with the expansion deviceinstalled and expanded (FIG. 10C), showing how the upper and lower lipsare inflated, displaced and flared forward, in the z-axis direction.

FIG. 11 is a perspective view of the cheek and lip expansion device ofFIG. 6, with the tongue guard shown separated from the cheek expansiondevice.

FIG. 12A is a front perspective view of another exemplary expanded cheekand lip expansion device.

FIG. 12B is a front perspective view of a cheek and lip expansion devicesimilar to that of FIG. 12A, but without any posterior crossbar.

FIG. 12C is a front perspective view of a cheek and lip expansion devicesimilar to that of FIG. 12A, without the posterior crossbar connectingposterior regions of the first and second upper and lower side members,but still including inwardly protruding extensions (e.g., a portion ofthe crossbar), to aid in loading the device against soft tissue coveringthe mandibular ramus.

FIG. 13A shows the device of FIG. 12A, with the frame partiallycollapsed from top to bottom.

FIG. 13B shows the device of FIG. 13A, showing a greater degree ofcollapse from top to bottom.

FIG. 13C shows the device of FIG. 13A, showing full collapse of theframe from top to bottom, with the lower frame portion latched to theupper frame portion.

FIG. 14A shows the device of FIG. 12A, with the frame partiallycollapsed from side-to-side.

FIG. 14B shows the device of FIG. 14A, with the frame further collapsedfrom side-to-side.

FIGS. 15A-15B show how the device of FIG. 12A may be placed into aperson's mouth using the top to bottom collapsibility of the device,with little or no reliance on the side-to-side collapsibility of thedevice. FIG. 15A shows one side of the device of FIG. 12A being placed(e.g., shoe-horned) into a person's mouth.

FIG. 15B is a progression from the state shown in FIG. 15A, showing theother side of the frame being positioned into the person's mouth.

FIG. 16A shows how the device of FIG. 12A may be placed into a person'smouth using both the top to bottom and side-to-side collapsibility ofthe device. In FIG. 16A, the upper and lower frame portions have beencollapsed and latched together, and the posterior arced regions pressedtogether, collapsing the device side-to-side, as well as top to bottom.

FIG. 16B shows the device of FIG. 12A in the mouth, with the mouth open,e.g., as placed using either the method of FIGS. 15A-15B or that of FIG.16A.

FIG. 16C is similar to that of FIG. 16B, but showing the person's jawbeing closed, with the device in the mouth.

FIGS. 17A and 17B illustrate how, with the cheek and lip expansiondevice in the mouth, the lips are not fully stretched side-to-sidearound the mouth, which permits asymmetric deformation of the person'slips to one side or the other without excessively stretching the lipsand causing pain to the patient.

FIGS. 18A-18D show how with the cheek and lip expansion device in themouth and the distal tip of the patient's tongue in the tongue guard,the patient is able to still move their tongue to either side, up, anddown.

DETAILED DESCRIPTION I. Introduction

The invention generally relates to intra-oral cheek and lip expansiondevices useful for expansion of soft oral tissues away from the dentalarches, isolating one or more teeth from soft oral tissue and creatingan enlarged working field. Such cheek and lip expansion devices mayinclude a selectively collapsible and expandable flexible and resilient(e.g., spring-like) frame for insertion into an oral cavity. Thecollapsed configuration facilitates insertion into the mouth, while theexpanded configuration, while positioned in the mouth, allows the frameto bear against and retract or displace soft oral tissue in multipledimensions and thereby isolate one or more teeth from soft oral tissueand create an enlarged working field. For example, rather than movingthe mandible down, the cheeks and lips may be displaced outward andforward in order to enlarge the working field, increasing space for thepractitioner to work and/or visualize the teeth, gums, or otherstructure.

The frame may include an upper frame portion and a lower frame portion,which are advantageously flexible and resilient (e.g., spring-like) soas to selectively assume collapsed and expanded configurations duringinstallation and use, as discussed more fully below. The flexibility ofthe upper and lower frame portions permits them to be selectivelycollapsed in a side-to-side (e.g., x-axis) direction and also anup-and-down (e.g., y-axis) direction to facilitate insertion of theframe, when in a collapsed configuration, into the oral cavity of apatient. After installation, the resiliency of the upper and lower frameportions causes them to expand outwardly in a spring-like fashion in atleast x-axis and y-axis directions to assume an expanded configurationinside the patient's oral cavity. The expanded frame inflates thepatient's mouth (e.g., like a tent or umbrella), displacing, comfortablyflaring, and retracting the cheeks and lips away from teeth of the upperand lower dental arches. Posterior loading, such as by abutment of aposterior regions of the frame against a posterior region of thepatient's mouth, may cause the frame to also exert force in a forward(or z-axis) direction in order to retract the patient's lips away fromteeth in the forward direction. In this way, the expansion device cancreate an enlarged and unobstructed working field in the oral cavity byretracting the cheeks and lips from a patient's teeth in a comfortable,umbrella-like fashion, instead of unnecessarily, excessively, anduncomfortably stretching the lips too far in a side-to-side (x-axis)direction, as typically occurs with prior lip retraction devices.

II. Exemplary Cheek and Lip Expansion Devices

FIGS. 1 through 5 illustrate an exemplary cheek and lip expansion device100. FIG. 1, for example, shows a cheek and lip expansion device 100comprising a frame 102 for insertion into an oral cavity (oral cavityand mouth may generally be interchangeably used herein). Frame 102further includes an upper frame portion 104 and a lower frame portion106, which are advantageously flexible and resilient so as toselectively assume collapsed and expanded configurations duringinstallation and use. In a collapsed configuration (e.g., see FIG. 3 andFIGS. 13A-14B), device 100 is more easily inserted into the oral cavity,while the expanded configuration (e.g., see FIG. 5) allows upper andlower frame portions 104, 106 to extend about the upper and lower dentalarches, respectively, and to bear against and retract soft oral tissuefrom adjacent teeth in multiple dimensions (e.g., in each of x-axis,y-axis, and z-axis directions) to create an enlarged working field forthe practitioner. Absent applied forces (or engagement of an optionallatching mechanism discussed below), frame 102 may assume the expandedconfiguration seen in FIGS. 1-4. The expanded frame 102 inflates ordilates the patient's mouth, displacing, flaring, and retracting tissueincluding the cheeks and lips away from the jaw and the teeth of theupper and lower dental arches. Posterior loading, such as by abutment ofa posterior end of frame 102 against a posterior region of the patient'smouth, causes frame 102 to also exert force in a forward (or z-axis)direction in order to retract the patient's lips away from teeth in theforward direction.

As further illustrated in FIG. 1, upper frame portion 104 includes upperside members 108, including a first (e.g., left) upper side member 108 aand a second (e.g., right) upper side member 108 b. Similarly, lowerframe portion 106 includes lower side members 110, including a first(e.g., left) lower side member 110 a and a second (e.g., right) lowerside member 110 b. References to “left” and “right” are made from theperspective of the practitioner facing the patient, although it is to beunderstood that the designation is arbitrary; the frame of referencecould alternatively be made from the perspective of the patient line ofsight (i.e., right becomes left and vice versa).

The upper side members 108 and lower side members 110 extend from arcedregions 116 a and 116 b. The first upper and lower side members 108 a,110 a may be joined at a first posterior frame region 116 a, and thesecond upper and lower side members 108 b, 110 b may be joined at asecond posterior frame arced region 116 b. Posterior frame arced regions116 may form flexible yet sufficiently rigid joints that resist bendingat a single point but rather distribute the bending radius along asubstantial length of upper and lower side members 108, 110 when upperand lower frame portions 104, 106 are collapsed together. This in turndistributes opening forces along a substantial portion of the length ofeach side member in order to bear against and effectively retract softoral tissues from the patient's teeth in both posterior and anteriorregions of the mouth. In another embodiment, a posterior hinge may beprovided that enables articulation between the upper and lower sidemembers 108 and 110.

In some embodiments, posterior frame arced regions 116 may each form acurved, bowed, v-shaped or u-shaped posterior joint on either side offrame 102. While posterior frame arced regions 116 may be generallydescribed as forming “v-shaped” or “u-shaped” posterior joints, theseterms are to be construed broadly. For example, any acute angularrelationship between upper and lower side members 108, 110 may beconsidered to be v-shaped or u-shaped. In addition, even if the angularrelationship between upper and lower side members 108, 110 weretechnically obtuse rather than acute, the terms “v-shaped” and“u-shaped” may be used to broadly encompass any such configurations solong as the radius of curvature between upper and lower side members108, 110 is smaller at the posterior end or region of frame 102 comparedto the anterior end or region. In some embodiments, posterior framearced regions 116 may represent the posterior most portions of upper andlower frame portions 104, 106.

The upper frame portion 104 may include an upper anterior connectingmember 112, which may be disposed between anterior regions of first andsecond upper side members 108 a, 108 b and which may include a firstupper connecting portion 112 a adjacent to first upper side member 108 aand a second upper connecting portion 112 b adjacent to second upperside member 108 b. Similarly, the lower frame portion 106 may include alower anterior connecting member 114, which may be disposed betweenanterior regions of the first and second lower side members 110 a, 110 band which may include a first lower connecting portion 114 a and asecond lower connecting portion 114 b.

The distance between a central point, apex or posterior-most region ofthe first and second posterior frame arced regions 116 a, 116 b definesa posterior width 120 of frame 120. The distance between anterior-mostregions of first and second upper side members 108 a, 108 b of upperframe portion 104 defines an upper anterior width 122. The distancebetween the anterior-most region of first and second lower side members110 a, 110 b of lower frame portion 106 defines a lower anterior width122′. In some embodiments, the posterior width 120 of frame 102 asdefined between upper and lower side members 108, 110 adjacent posteriorframe ends 116 (e.g., the distance between the vertex of angled firstposterior frame end or joint 116 a to the vertex of angled secondposterior frame end or joint 116 b) is greater than the upper and loweranterior widths 122, 122′ of upper and lower frame portions 104, 106.

In some embodiments, the upper and lower anterior widths 122, 122′ ofupper and lower frame portions 104, 106, respectively, can also differfrom one another. In some embodiments, the upper anterior width 122 ofupper frame portion 104 can be greater than the lower anterior width122′ of lower frame portion 106, such as to account for anatomicaldifferences in size between a patient's upper and lower dental arches,with the upper dental arch typically being wider and encompassing orsurrounding the lower dental arch in the anterior region when the teethare brought together, with the upper incisors and cuspids generallyextending over and forward of the lower incisors and cuspids.

Expansion device 100 may be designed to have different sizes dependingon the facial anatomy of the patient (which may be determined, forexample, by the spacing between the eyes and/or whether the patient is asmall child, growing child, or adult). In some embodiments, expansiondevice 100 may have a posterior width 120 in a range of about 90-130 mm(e.g., about 95-110 mm, about 100 mm, or about 115-120 mm) and anteriorwidths 122, 122′ in a range of about 50-90 mm. For example, the upperanterior width 122 of upper anterior connecting member 112 may be in arange of about 70-90 mm. Where the lower anterior width 122′ of loweranterior connecting member 114 is less than the upper anterior width 122of upper anterior connecting member 112, it may be in a range of about50-90 mm. In some embodiments, the posterior width 120 may be from about20% to about 100%, from about 20% to about 80%, from about 25% to about75%, or from about 30% to about 50% (e.g., about 40%-50%) greater thaneither the upper or lower anterior widths 122, 122′. In someembodiments, the posterior width 120 can be greater than the upperanterior width 122, which may be greater than the lower anterior width122′. By way of example, with a posterior width of about 100 mm, anupper anterior width of about 70 mm, and a lower anterior width of about50-55 mm, the posterior width 120 is about 40% greater than the upperanterior width 122, and about 90-100% greater than the lower anteriorwidth 122′. The upper anterior width 122 may in turn be from about 15%to about 80%, from about 25% to about 75%, or from about 30% to about50% (e.g., about 40%) greater than the lower anterior width 122′.Providing a greater upper anterior width 122 as compared to loweranterior width 122′ better conforms to the actual anatomy of a typicalpatient, as the upper dental arch is typically wider across its anteriorregion than the lower dental arch. This configuration provides bettercomfort and a better fit as upper and lower connecting members 112, 114are received within corresponding upper and lower anterior vestibules ofthe mouth.

In addition, a larger posterior width 120 advantageously provides aconfiguration by which expansion device 100 tends to pull itself intothe patient's mouth and be retained therein, as opposed to exhibiting atendency for a cheek or lip retractor to be pushed out of the patient'smouth, which is typical of many existing devices. In addition, thisfeature helps improve the ease of insertion of expansion device 100,particularly in combination with the side-to-side collapsibility thatmay be provided by the flexible and resilient spring-like frame 102. Forexample, the posterior width 120 can be collapsed side-to-side to have awidth that is less than anterior widths 122, 122′ during insertion, ifdesired (see FIGS. 14B and 16A), and then the posterior width 120expands once released within the mouth, helping to pull the device backinto the mouth, and to maintain it there so long as desired.

In addition to or instead of the upper anterior width 122 being greaterthan the lower anterior width 122′, the total length of upper frameportion 104 can be greater than the total length of lower frame portion106. In some embodiments, the total length of upper frame portion 104 isthe combined lengths of first and second upper side members 108 andupper anterior connecting member 112, and the total length of lowerframe portion 106 is the combined lengths of first and second lower sidemembers 110 and lower anterior connecting member 114. The overalllengths of upper and lower frame portions are shown in FIG. 6, whichshows another embodiment of a cheek and lip expansion device. Theoverall length of the upper frame portion is designated L_(U), while theoverall length of the lower frame portion is designated L_(L).Differences in length between upper and lower frame portions 104, 106can account for anatomical differences in length and size between theupper and lower dental arches of a patient, and the associated upper andlower vestibules of a typical patient. Many existing cheek or lipretraction devices do not account for such differences, but rathermirror the bottom half of the device relative to the top half, whichdecreases both effectiveness and comfort.

To further account for anatomical differences between upper and lowerdental arches, side members 108, 110 of upper and lower frame portions104, 106 may differ from one another in length. For example, sidemembers 108 of upper frame portion 104 may be somewhat shorter or longerthan side members 110 of lower frame portion 106. For example, upperside members 108 may be shorter than lower side members 110, althoughupper frame portion 104 may have an anterior width 122 and overalllength that are greater than the anterior width 122′ and overall lengthof lower frame portion 106, as described above. All such characteristicsmay be provided to better fit the anatomy of the upper and lower dentalarches and associated upper and lower vestibules into which the upperand lower frame portions are received. They can be customized based ondifferences in anatomy, size, age, gender, and the like.

As illustrated in FIG. 1, frame 102 may include a posterior crossbar 124positioned between first and second posterior ends 116 a, 116 b. In someembodiments, the crossbar 124 may include first and second posteriorlycurved portions 124 a, 124 b. Posterior crossbar 124 may include acurved, bowed, v-shaped or u-shaped anteriorly curved portion 126 (e.g.,centrally located along posterior crossbar 124 between the first andsecond curved portions 124 a, 124 b, if present). Each of theposteriorly curved portions 124 a, 124 b and the anteriorly curvedportion 126 may increase flexibility and resilience of the posteriorcrossbar 124 to better facilitate side-to-side collapse of frame 102(e.g., by moving first and second posterior ends 116 a, 116 b towardeach other). Thus, frame 102 may be collapsible in a side-to-sidedimension (e.g., x-axis direction) as well as a top-to-bottom dimension(e.g., y-axis direction). Such multi-dimensional collapsibility greatlyimproves the ease of insertion, facilitating single-handed insertion andinstallation in a patient's mouth. Single-handed insertion can befurther facilitated by providing a latch mechanism, which can latchupper and lower frame portions 104, 106 together, as described infurther detail below. A latch mechanism could also be provided forholding frame 102 in a side-to-side collapsed configuration if desired.Such collapsed configuration is described in further detail inconjunction with FIGS. 13A-14B.

In an embodiment, posterior crossbar 124 may be connected to either sideof upper frame portion 104 and lower frame portion 106 by first andsecond floating gussets 128 a, 128 b, which provide a pair ofconnections bridging first and second posterior ends or joints 116 a,116 b. For example, second floating gusset 128 a may connect with rightupper side member 108 b at upper connection point or region 129 a andwith right lower side member 110 b at lower connection point or region129 b. First floating gusset 128 a may be similarly connected with upperand lower side members 108 a, 110 a. Floating gussets 128 may provideadditional rigidity that increases upward, opening curvature or force toframe 102, resists collapse, and directs applied collapsing forces awayfrom (or anterior to) posterior ends or joints 116 and toward connectionpoints or regions 129 a, 129 b on each side of the floating gusset. Suchstructure may direct bending of upper and lower frame portions 104, 106as they are selectively collapsed or expanded in a top to bottomdimension (e.g., y-axis direction). Floating gussets 128 may alsofacilitate easier side-to-side collapsibility when applying side-to-sideforces, as posterior crossbar 124 is not directly connected to upper andlower frames 104, 106 at posterior ends 116 but at points spaced apartfrom the apex or vertex of posterior ends 116.

Upper and lower frame portions 104, 106 may further include upper andlower lip protecting members 130 and 132, respectively. Upper lipprotecting member 130 may be centrally disposed on or in upper anteriorconnection member 112 (e.g., between first upper connecting portion 112a and second upper connecting portion 112 b) and extend laterallyforward from upper frame portion 104 in order for upper lip protectingmember 130 to extend away from the patient's oral cavity and over thepatient's upper lip during use. Lower lip protecting member 132 may besimilarly disposed along lower anterior connection member 114 or lowerframe portion 106 so as to extend away from the patient's oral cavityand over the patient's lower lip during use.

Upper and lower lip protecting members 130, 132 may curve over andprotect the central portion of a patient's upper and lower lips during adental procedure. In addition, as perhaps best seen in FIG. 1, lipprotecting members 130 and 132 may provide recesses or troughs 105 a and105 b above and below generally horizontal anterior lines defined byanterior connecting members 112, 114 of upper and lower frame portions104, 106, respectively. Such troughs can be designed to further enlargethe working field available to the practitioner in the region of thepatient's upper and/or lower incisors, while at the same time coveringand protecting the central portion of the patient's lips. In at leastthe case of the upper recess or trough 105 a, it may also avoidirritating contact with the bony structure in the central portion of theupper vestibule where the recess 105 a is disposed when in the mouth. Inan embodiment, lip protecting members 130, 132 may be made from astiffer material than other frame portions of device 100, which arerelatively flexible and resilient. In addition to the benefits describedabove, lip protection members 130 and 132 may also serve as an emergencyremoval handle should the device need to be removed quickly. Even wherequick removal may not be needed, lip protection members may present aportion of structure 100 that may be easily and readily grasped by thepractitioner when the device is to be removed. Advantageously, thesemembers may be the only structure protruding from the person's mouthduring use, with the lip protection members covering the central portionof the person's upper and lower lips, rather than the sides thereof, soas to not unnecessarily stretch the patient's lips open fromside-to-side to the extent that many other retraction devices do.

Furthermore, as perhaps best seen in FIG. 3, lip protecting members 130,132 may be selectively engagable with one another when upper frameportion 104 is folded towards lower frame portion 106 so as to latchupper 104 and lower 106 frame portions together. Of course, whilesometimes described herein in terms of upper frame portion 104 beingfolded downward towards lower frame portion 106, it will be understoodthat one or both frame portions may move during such collapse so thatlower frame portion 106 may similarly be collapsed toward upper frameportion 104.

An example of such folding and latching is illustrated in FIG. 3, wherethe expansion device is shown both before folding (in solid lines), andafter folding (with the upper frame portion 104 shown again in brokenlines). FIGS. 13A-13C, described in further detail below, furtherillustrate top to bottom collapse of another similar cheek and lipexpansion device. Such a latching mechanism may be used to lock upperand lower frame portions 104, 106 in a closed, collapsed configurationprior to insertion into the patient's mouth. As a result of the devicebeing latched in a configuration where it is collapsed in theupper-to-lower dimension, the practitioner is not required to hold thedevice in this collapsed configuration (it may be maintained untilreleased), allowing the practitioner to more easily configure and holdthe device in a side-to-side collapsed configuration during insertion.Such methods of insertion are described in further detail below inconjunction with FIGS. 15A-16B.

Once cheek and lip expansion device 100 is inserted into the patient'smouth, the latch mechanism may be released to allow frame 102 to expandwithin the patient's mouth. For example, if upper 104 and lower 106frame portions are latched together, a practitioner may use one hand tosqueeze posterior sides of frame 102 together in a side-to-side manner,and insertion may be easily done with one hand, if such insertion isdesired. Of course, two-handed insertion is also possible. Differentmechanisms for latching upper and lower frame portions 104, 106 (e.g., alatch structure separate from any lip protection members) mayalternatively or additionally be provided. Such additional latchstructure could also be provided for latching any side-to-side collapseof any of the devices disclosed herein, as well. Some such latchingmechanisms are described in further detail in conjunction with theembodiments of FIGS. 6-16B, below.

Expansion device 100 may also include a tongue guard 134, which may beselectively removable. For example, this may allow attachment or removalof tongue guard 134 from posterior crossbar 124, even while expansiondevice 100 is installed within an oral cavity of a patient. While tongueguard 134 may be removed while device 100 is installed within an oralcavity of a patient, it may also be removed prior to insertion, afterinsertion or removal, or at any point in the procedure. Tongue guard 134may be coupleable to posterior crossbar 124 through any suitablemechanism (e.g., friction fit, press-fit, keyed coupling, etc.). Forexample, a protrusion and receptacle configuration shared between tongueguard and posterior crossbar 124 may allow tongue guard 134 to “click”into place once seated.

Tongue guard 134 may serve to prevent activation of a patient'spharyngeal reflexes (i.e., gag reflex) and to prevent the flow ofsaliva. In some patients with a sensitive or “strong” pharyngeal reflex,it may be desirable to remove tongue guard 134 from the expansion device100. A removable tongue guard 134 permits expansion device 100 to beused with or without tongue guard 134, depending on patient need orpreference. In an embodiment, aspiration may be provided through tongueguard 134 (e.g., it may include perforations or holes formedtherethrough). Tongue guard 134 may be formed of the same or a differentmaterial than other portions of expansion device 100. For example, amaterial that is particularly flexible, soft and adaptable (e.g.,silicone or a thermoplastic elastomer) may be preferred. While tongueguard 134 is shown as a simple stop against which the tongue may press,in other embodiments, the tongue guard may partially or substantiallyfully encapsulate or envelop at least a portion of the tongue, such asthe distal end of the tongue. Examples of such tongue guards (e.g.,tongue guard 234) are described in further detail below, in conjunctionwith FIGS. 6-16B. The tongue guard may advantageously be supported onposterior crossbar 124 in a manner that permits it to move somewhat up,down, or from side-to-side (e.g., to allow the patient some ability tomove the tongue during a procedure). A tongue guard and the centralportions of crossbar 124 (e.g., anteriorly curved portion 126) may pushforward as device 100 is collapsed side-to-side, as apparent in FIGS.14A-14B. Upon relaxation of such a side-to-side collapsing force, thetongue guard and central portions of cross bar 124 may again movebackward (posteriorly) as frame 102 is expanded.

As well illustrated in FIGS. 2 and 3, expansion device 100 may alsoinclude one or more bumpers or enlarged, thickened portions 138 on frame102, positioned for receipt into the anterior corners of the upper andlower vestibules (e.g., the area between the teeth and dental arch lips,and cheeks) at anterior corners of the upper and lower frame members.Such bumpers 138 may also provide increased surface area to which acushioning material may be applied (e.g., a cover over the bumpers), toprovide additional cushioning to specific areas of the mouth. Theembodiment of FIG. 6 illustrates such bumper covers 238′ over thebumpers. For example, a pair of anterior thickened bumpers 138 on eachof upper and lower frame portions 104, 106 may be provided at anteriorcorners where side members 108, 110 intersect with anterior connectingmembers 112, 114. In addition, left and right side members 108 a, 108 bmay be thickened in various regions, such as adjacent to posterior ends116 to form thickened posterior regions 140. Bumpers 138 and thickenedposterior regions 140 may comprise enlarged, thickened portions of frame102 as compared to adjacent portions of frame 102, to increase surfacearea contact with soft tissues in these regions, providing increasedcomfort as bumpers 138 bear against soft oral tissue. The thickenedcharacteristics of the these thickened regions may also increase theirrigidity and resistance to bending as compared to adjacent, thinnerregions of the frame. Such increased rigidity aids in lip lifting andretraction or expansion, forcing the lips to flare upwardly andforwardly.

Thickened regions 140 at posterior ends 116 may resist bending at adistinct point of posterior ends or joints 116, so as to form a bendableradius that resists bending at a single distinct point, but ratherdistributes the bending forces anteriorly, along the length of the sidemembers 108, 110. Some bending forces may also be distributed to regionsnear or adjacent to upper and lower anterior connecting members 112,114. Such bending forces may particularly cause bending to occur at moreanterior, thinner portions of the side members 108, 110 (e.g., withinthe thinner central portions of side members 108 and 110) during top tobottom collapse. Bumpers 138 and/or thickened posterior regions 140 atposterior ends 116 may also provide improved access to the oral cavityby the practitioner, better holding back adjacent soft tissue. Duringuse, first and second lower side members 110 a, 110 b of lower frameportion 106 may reside within the lower facial vestibule, and first andsecond upper side members 108 a, 108 b of upper frame portion 104 mayreside within the upper facial vestibule. Upper and lower anteriorconnecting members 112, 114 may reside within the upper and loweranterior vestibules, respectively. Thickened posterior regions 140 maybear against the rear of the facial vestibules, pushing the deviceforward, with thickened bumpers 138 residing in the corners at thetransitions between the facial portion and anterior portion of the upperand lower vestibules. Such bumpers 138 may aid in holding the softtissues back from the teeth, and flaring the lips and cheeks forward andoutwardly.

Anterior bumpers 138 may be located at or near anterior corners of upperand lower frame portions 104, 106 so that upper and lower anteriorbumpers 138 serve to cushion the anterior cheek soft tissue adjacent thecorners of the patient's mouth. The thickened posterior regions 140similarly cushion the posterior cheek soft tissue towards the back ofthe patient's mouth, adjacent the jaw, backwall of the vestibule, andthe ramus.

Many existing retraction devices tend to “grab” the corners or far sidesof the patient's mouth, uncomfortably stretching the lips in aside-to-side dimension. Bumpers 138 aid in reducing or eliminating anysuch tendency, greatly increasing the comfort of the device as comparedto available alternatives. In addition, as seen in FIG. 5, there are nostructures at the sides of the opening of the mouth that wrap around orgrab the lips, forcing them far open side-to-side, as do many otherdevices. Rather, the only engagement with the outside of the lip occursat the top and bottom of the mouth, with lip protecting members 130,132. In addition, many retractors include a large continuous round oroval ring that extends about the lips on the anterior portion of themouth to stretch the lips open. Such a ring pulls the lips side-to-side,causing them to be stretched open side-to-side to an uncomfortabledegree. The sides of such a ring do not rest within upper or lowervestibules, but pass therebetween. No such anterior ring is necessary orrequired with the present frame. Rather, the upper and lower frameportions may reside entirely within the upper and lower vestibules.

FIGS. 6 through 11 illustrate another exemplary cheek and lip expansiondevice 200, similar to device 100. Device 200 similarly includes aflexible and resilient (e.g., spring-like) frame 202 that is selectivelycollapsible and expandable. Frame 202 may include an upper frame portion204, which may extend about the upper dental arch and bear against andretract cheeks and/or lips from teeth of the upper dental arch, and alower frame portion 206, which extends about the lower dental arch andretracts cheeks and/or lips from the jaw and teeth of the lower dentalarch. Upper frame portion 204 may include first or left side member 208a and right or second side member 208 b. Similarly, lower frame portion206 may include left or first side member 210 a and right or second sidemember 210 b. First side members 208 a, 210 a may be joined to oneanother at their posterior ends to form a first posterior frame end orjoint 216 a, and second side members 208 a, 210 b may be joined to oneanother at their posterior ends to form a second posterior frame end orjoint 216 b on an opposite side of frame 202. While described forsimplicity as including various distinct portions or members, it will beappreciated that in some embodiments, any number of such sections orparts of the frame 202, or the entire frame 202, may be a one-piece,monolithic, or unibody structure, e.g., that may be integrally formedfrom a single piece of material (e.g., injection molded as such). Thus,where various ends or joints are described, it will be appreciated thatsuch members or portions need not actually be separate, and then joinedtogether (although such is certainly also possible)

An upper anterior connecting member 212 may be disposed between theanterior regions of upper side members 208 a, 208 b. A lower anteriorconnecting member 214 may be disposed between the anterior regions oflower side members 210 a, 210 b. Upper anterior connecting member 212may include first upper connecting portion 212 a adjacent to first upperside member 208 a and a second upper connecting portion 212 b adjacentto second upper side member 208 b, while lower anterior connectingmember 214 may include first lower connecting portion 212 a adjacent tofirst upper side member 208 a and a second lower connecting portion 212b adjacent to second upper side member 208 b. Upper anterior connectingmember 212 is shown as being upwardly extended adjacent the centralportion of upper frame portion 204 (e.g., corresponding to upper lipprotecting member 230), rather than simply running generallyhorizontally across the anterior side (as line L_(U) does). Such upwardextensions 213 create an additional recessed space 205 a adjacent theupper anterior connecting member 212 and upper lip protecting member230. This space advantageously keeps the upper anterior connectingmember 212 from uncomfortably contacting bone in this region of theanterior upper vestibule. The lower anterior connecting member 214 isshown as extending generally horizontally across this analogous space,as the upper and lower vestibule anatomy is different. Of course, ifdesired, a similar outward recessed extension could be provided here,removing the cross-member portion of 214 that spans the connectionpoints of lower lip protecting member 232 such that first and secondportions 214 a and 214 b of the lower anterior connecting member 214connect only to the connection points of the lower lip protecting member232, thereby providing an additional flex or relief point. In otherwords, first and second portions 214 a and 214 b may not run generallyhorizontally, continuously between the anterior regions of lower sidemembers 210 a and 210 b, but may include a forward extension and recessanalogous to recess 205 a in the upper frame portion.

As with device 100, a posterior width 220 of upper 204 and lower 206frame portions as defined between posterior regions 216 may be greaterthan upper anterior width 222 and/or lower anterior width 222′ of theupper 204 and lower 206 frame portions, respectively. Such relationshipsmay be as described previously in the context of device 100, whereposterior width 220 is greater than upper anterior width 222, and upperanterior width 222 is greater than lower anterior width 222′. Alsosimilar to device 100, frame 202 may also include a posterior crossbar224 extending between posterior regions 216 a and 216 b. Because of thegreater posterior width, the side members 208 a, 210 a, and 208 b, 210 bfrom posterior ends 216, anteriorly forward, may be angled inwardly,towards the centrally disposed lip protecting members.

Illustrated upper and lower lip protecting members 230 and 232 are alsosomewhat different than those illustrated with device 100. Both members230, 232 may include a hollow portion 230 a, 232 a, respectively. Upperlip protecting member 230 may include a cross-member 231 adjacentportion 230 a, which cross-member 231 may serve to latch with acorresponding latch member 233 of lower lip protecting member 232. Inaddition, the upper lip protecting member 230, particularly as it isextended upward due to extensions 213, may act as a flex or relief pointat which the various portions of the upper frame (e.g., upper anteriorconnecting member portions 212 a, 212 b, lip protecting member 230,etc.) may begin to arc or bend to provide increased compliance andresiliency. As with device 100, lip protecting members 230 and 232 maycurve over and protect the patient's lips during a dental procedure,extending outside the patient's mouth. Because of their extensionoutside of the mouth, they provide a convenient handle that can begripped when removing or positioning the device. FIGS. 8 and 13C-14Bshow the lip protecting members 230 and 232 selectively engaged with oneanother, with cross-member 231 latched with latch member 233. Forexample, cross-member 231 may snap or compression fit under latch member233, holding cross-member 231, and thus upper frame portion 204 latchedto lower frame portion 206. Tongue guard 234 is not shown in FIG. 8 soas to more clearly show the other structures. As seen in FIG. 8, theside view of the expanded expansion device may be generally L-shaped, asdefined by the upper and lower frame portions.

Instead of floating gussets 128, posterior crossbar 224 of device 200may be connected directly to the posterior ends of side members 208 and210, e.g., at the location of joints or posterior arced regions 216.Posterior crossbar 224 may include a curved, bowed, v-shaped or u-shapedanteriorly curved portion 226 (e.g., centrally located along crossbar224) to facilitate side-to-side collapsibility of device 200. As shown,a cross-member portion 227 of crossbar 224 may extend between the endsof v-shaped or u-shaped portion 226 (e.g., providing a triangular shapedportion in crossbar 224). The anteriorly curved portion 226 and thecross-member portion 227 may also aid in removably attaching a tongueguard 234, as shown. In some embodiments, the crossbar 224 may includefirst and second posteriorly curved portions 224 a, 224 b, which may beprovided on either side of curved portion 226, if present, e.g., withfirst curved portion 224 a between posterior end 216 a and centrallydisposed curved portion 226, and second curved portion 224 b betweenposterior end 216 b and centrally disposed curved portion 226.

Tongue guard 234 is shown as differently configured than tongue guard134 of device 100. Tongue guard 234, may be selectively removable (e.g.,via a snap-fit compression-fit, or similar, as shown (e.g., FIG. 11shows the tongue guard 234 detached). For example, a top surface oftongue guard 234 may include a recess 236 corresponding to curvedportion 226, allowing curved portion 226 to snap into recess 236,attaching tongue guard 234 to posterior crossbar 224, within centrallydisposed anteriorly curved portion 226. The expansion device 300 seen inFIG. 12A is similar to expansion device 200, but without the crossmember portion 227 that extends fully across the rear of anteriorlycurved central portion 226. Rather, expansion device 300 includes aretention feature such as retention protrusions 227′, which allowstongue guard 234 to be pressed into place from the rear of curvedportion 226, and retention protrusions 227′ flex to allow receipt of thetongue guard therein, and then spring back, retaining the tongue guardin place. Without such protrusions, the tongue guard may be more likelyto fall out. For example, retention protrusions 227′ may extend inwardlyfrom opposite sides of first and second curved members 224 a, 224 b, orfrom oppositely inwardly oriented sides of anteriorly curved portion226. Tongue guard 234 may be configured as a sheath, which may be closedat the anterior end, closed along the top, and open at the posteriorend, so that the tongue may be introduced therein. The bottom end mayalso be largely open (see FIGS. 9 and 18C). As such, structure 234 mayserve as a garage into which the tongue may be introduced, so as toensure the tongue does not interfere with practitioner access to thedesired areas of the oral cavity, while also protecting the top distalend of the tongue as it is enveloped by guard 234.

When the patient's tongue is received within guard 234, the naturallyapplied force may push the expansion device 200 forward (e.g., 1-4 mm),causing a further expansion of expansion device 200 within the oralcavity, to create an even greater clearance around the dental arches(i.e., between the dental arches and the cheeks and/or lips, as well asbetween the tongue (tongue guard 234) and the lingual dental archsurfaces). Such forwardly applied force may work in conjunction withposterior loading of the device, e.g., as provided by loading of thecrossbar 224 against the soft tissue covering the mandibular ramusand/or by loading of the posterior ends 216 on the backwall of thevestibule. Such abutment and loading of the frame relative to themandibular ramus and posterior tissue of the oral cavity may result inincreased three-dimensional inflation of the cheeks and lips in x-axis(side-to-side), y-axis (top-to-bottom), and particularly z-axis(forward) dimensions.

Clearance provided between the dental arch and the soft tissue of thecheeks and/or lips with the device in place may depend on the particularanatomy of a given patient, but may typically be as much as 2 cm, e.g.,at least about 4 mm, at least about 8 mm, at least about 12 mm, etc.FIG. 10A shows a typical clearance (C) in the lower vestibule, aroundthe entire buccal side of the lower dental arch of 4 mm to about 2 cm,also showing good clearance on the lingual side of the lower dentalarch, between the tongue guard 234 and the dental arch. As seen, thedevice is able to retract both the lips and the cheeks away from thedental arch, providing excellent clearance all around. All of this isadvantageously accomplished without expanding the lips side-to-side toan extent that would be uncomfortable to the patient, as is oftenprovided by other existing cheek or lip retractor devices. Rather, muchof the retraction or expansion is achieved by pushing the lips forward,and the cheeks outwardly, rather than simply opening the mouth, andstretching the lips side-to-side as far as possible as in many priorretraction devices. Because of this difference, it is possible for thepractitioner to asymmetrically pull one cheek or the other to one sideor the other, for a wider working field on a given side, as shown inFIGS. 17A-17B. While shown with use of a tongue guard, of course, any ofthe devices according to the present invention may be employed with orwithout a tongue guard.

FIGS. 10B and 10C show the side profile of the patient, both before(FIG. 10B) and after (FIG. 10C) installation and expansion of thedevice. FIG. 10C shows how the upper and lower lips of the patient areflared and inflated forward, in the z-axis direction upon expansion ofdevice 200. The clearance C thus provided in the z-axis direction,between the upper lip and the upper dental arch is provided as the upperanterior connecting member 212 resides within the upper anteriorvestibule, and the frame 202 is posteriorly loaded. For example, theposterior arced regions 216 may abut against the backwall of the facialvestibules, and portions 224 a and 224 b of posterior crossbar 224 mayabut against the soft tissue over the ramus, pushing the expansiondevice 200 forward, so that upper anterior connecting member inflates,displaces, and flares the upper lip further away from the upper dentalarch than would otherwise be the case. Similarly, the lower anteriorconnecting member 214 resides within the lower anterior vestibule, andthe same posterior loading described above similarly results ininflation and flaring of the lower lip forward, in the z-axis direction,away from the lower dental arch. Because of the anatomical differencesdescribed above in reference to the length of the upper side members 208relative to the lower side members 210 (i.e., longer upper sidemembers), in at least some embodiments, the upper lip may be flared outfurther than the flaring (Δz) provided to the lower lip. Of course, thelower lip may also be flared out further, depending on the specificgeometry of the expansion device. As seen in FIG. 10C, as the expansiondevice 200 may also default the patient's jaw to an open position (dueto the resilient top to bottom opening or loading force provided betweenthe upper and lower frame portions 204, 206 in the expandedconfiguration), the upper and lower lips may also be directed upwardsand downwards, respectively, (in the y-dimension).

As will be apparent from FIGS. 10A-10C, when installed, the expansiondevice pushes out on the lips and the cheeks simultaneously, retractingthese soft tissues away from the dental arches. In that configuration,particularly when employed with a tongue guard such as guard 234, thedevice “floats” within the mouth, acting as a tent or umbrella frame toexpand the lips and cheeks (which are the “web”). The posterior crossbar224 and/or posterior ends 216 may engage soft tissue covering themandibular ramus, further pushing the device forward, as it “floats”within the mouth. Because of its “floating” and posteriorly loadedconfiguration, the posterior loading (which may be enhanced by theperson pressing the tongue forward in guard 234) can shift the device asa whole forward (e.g., 1-4 mm) in the z-axis direction, creatingsignificantly more useful retraction of the cheeks and lips, as comparedto existing devices, which are not configured to provide such posteriorloading, and forward, z-axis inflation and flaring.

The described expansion devices also provide improved retraction orexpansion adjacent the posterior regions of the dental arch, providingexcellent clearance all around the dental arch, including the rearmolars (e.g., the 2^(nd) molars) or other posterior teeth, without thedevice blocking or impeding practitioner access to these areas aroundthe posterior teeth. In addition, there is no need for an anteriorcontinuous ring that circles the opening of the mouth, which caninterfere with access to the cuspids and bicuspids. For example, such aring present in the anterior portions of the oral cavity, between thecheeks or lips and the teeth, necessarily cross from the upper to lowervestibules or other portions of the mouth. Because such crossing occursin the anterior region of the mouth (e.g., near the cuspids and/orbicuspids), it places frame structure where it interferes with theability to access these tooth positions. The upper and lower frameportions of the present expansion devices rather runanteriorly-posteriorly, within the vestibule, and thus can avoidcrossing from upper to lower regions of the mouth (and thus crossingover some tooth positions). Rather, no such upper to lower crossingoccurs in the vicinity of the dental arches, but occurs only behind thedental arches, at posterior ends 216.

Returning to FIG. 6, one or more bumper covers 238′ may be provided overenlarged, thickened corner bumpers on frame 202. While the anteriorthickened corner bumpers on frame 202 are covered so as to not bevisible in FIGS. 6-11, they may be similar or identical to anteriorcorner bumpers 138 seen in FIGS. 1-5, or those (238) of FIGS. 12A-16A.Such underlying thickened corner bumpers provide increased surface areafor overmolding or otherwise bonding of softer, bumper covers 238′thereover. In an embodiment, such bumper covers 238′ may comprise adifferent material than adjacent frame 202, e.g., comprising a softer,flexible, and/or elastomeric material overmolded with respect to frame202. For example, bumper covers 238′ may have a Shore A durometer in arange from 0 to about 50, from 0 to about 25, or about 15. Tongue guard234 may similarly be formed of a different material than frame 202, andmay have durometer characteristics that are harder than bumper covers238′. For example, tongue guard 234 may have a Shore A durometerhardness in a range from about 50 to about 100, from about 50 to about90, or from about 60 to about 80. The tongue guard may comprise amaterial having greater flexibility and/or elasticity than the flexiblespring-like frame.

Any device according to the present invention may advantageously allowfull closure of the patient's mouth, with the device installed, as seenin FIGS. 17A-17B. This is a distinct advantage over many existing cheekor lip retractor devices, where full closure of the jaw is not possible.Because closure of the jaw is possible, a practitioner may perform abite-check without having to remove the device. As illustrated in FIGS.10A-10C, the devices 100 and 200 provide excellent displacement,retraction or expansion of both the lips and the cheeks, so as toprovide a large clearance area (C) around the teeth where thepractitioner would like to access, yet without stretching the lips in aside-to-side dimension to their limit. Such clearance provides excellentresults for introduction of a dental drill, or for use with anintra-oral scanner, for example, to scan the dental and/or oralstructures within the mouth (e.g., for digital crown manufacture).Another advantageous use of the expansion device may be for in-officetooth bleaching. Because the device provides such excellent clearancearound the dental arches (i.e., between the dental arch and adjacentsoft tissue cheeks and lips), there is less risk of contact betweenirritative tooth bleaching compositions and such soft tissues, which mayotherwise irritate or burn the soft tissues.

In addition to allowing full closure of the jaw, the expansion devicesaccording to the present invention may be configured so as to not blockor impede practitioner access to the posterior teeth of a patient. Forexample, this may typically include bicuspids in children, or first andsecond molars (or even third molars) in adults. This is advantageous, assome retraction devices do not provide good access to the posteriorteeth, particularly the rear molars. For example, the side members(e.g., 208 and 210) and posterior crossbar (224) may tend to extendbucally, and generally parallel to, and then wrap around the dentalarch, behind the rear molars. The crossbar 224 may reside in aretromolar region, e.g., between the ramus and the molars. In addition,as described above, the inclusion of thickened corner bumpers (e.g.,138, 238) within the anterior corners of the frame allows thesethickened portions to reside within the anterior corners of thepatient's vestibule, aiding in flaring the lips forward, and reducingany tendency of the device to uncomfortably “grab” or “jab” the cornersof the mouth of the patient.

According to an embodiment, the frame of any of the embodiments maytypically be formed from a polymeric material. For example, the framemay be injection molded or otherwise formed a thermoplastic or othersuitable polymer material (e.g., all as a single piece of material). Inanother embodiment, the frame may be formed of a shape-memorynickel-titanium alloy exhibiting a martensitic transformationtemperature between ambient temperature (e.g., about 20° C.) and bodytemperature (e.g., 37° C.). Such a shape memory alloy could allow theexpansion device to be highly deformable at ambient temperature prior toand during insertion, while become rigid as it warms to bodytemperature. This would be advantageous in practice because the alloycould be flexible and easily deformed before insertion, while stillproviding excellent retraction after warming up to body temperature.Inexpensively manufactured polymeric expansion devices may be intendedfor single use, so as to be disposed of after a single use. Plasticmaterials exhibiting sufficient flexibility for the frame have beenfound to provide excellent results. The flexibility may result from thegeometry, e.g., the thinness of at least some portions of the variouselongate members. For example, side members 208 and 210 include thinnercentral portions between their thickened posterior ends 240 and theirthickened anterior ends 238, allowing the members to flex and bend asneeded for collapsibility. The posterior crossbar 224 is similarlyflexible due to its geometry, including the thinness of the crossbar,and the variously curved portions (e.g., 224 a, 224 b, and 226). In anycase, the frame and its material is sufficiently flexible so as to allowflexing of the upper and lower frame portions towards one another, aswell as flexing of the left and right sides towards one another. Whenreleased, the frame is able to recoil back to an expanded configuration.Some models, such as one formed of a shape memory nickel-titanium alloy,may be autoclaved or otherwise sanitized following use, so as to allowreuse of the device.

A device in which the frame is formed of a shape memory nickel-titaniumalloy may further include an exterior coating (e.g., silicone, anysuitable overmolded plastic, or other coating otherwise encapsulatingthe Ni—Ti frame) to retard (e.g., insulate) the temperature inducedphase transformation of the nickel-titanium alloy. Such a coating maycontrol the rate of heating of the frame after insertion, allowingretraction or expansion to occur at a gradual, comfortable and gentlepace.

FIGS. 12A-12C show further exemplary cheek and lip expansion devicesaccording to the present invention. FIG. 12A shows a device 300 similarto device 200, but without the bumper covers 238′, and without acontinuous cross-member 227 spanning central anteriorly curved portion226. Device 300 includes a flexible spring-like frame 202, including anupper frame portion 204 and a lower frame portion 206 which are flexibleand resilient so as to selectively assume collapsed and expandedconfigurations during installation and use. As with device 200, bothupper and lower frame portions 204 and 206 include upper side members208 and lower side members 210. Upper anterior connecting member 212joins together the anterior portions or ends of the first and secondupper side members 208 a and 208 b. Lower anterior connecting member 214joins together and extends between the anterior portions or ends of thefirst and second lower side members 210 a and 210 b. The posteriorregions of the first upper and lower side members 208 a, 210 a arejoined at posterior arced region 216 a, while the posterior regions ofthe second upper and lower side members 208 b, 210 b are joined atposterior arced region 216 b. Posterior regions 216 form flexible yetsufficiently rigid joints that resist bending at a single point, butrather distribute the bending moment along a substantial length of theupper and lower side members 208, 210 during collapse along the y-axis.Distribution of the bending or flexing forces associated with top tobottom collapse of the expansion device is aided by providing theposterior ends of side members 208 and 210, where they join (atposterior regions 216) with a thickened structure 240, so that thethickened cross-section at the posterior regions 216 a, 216 b resistbending, forcing the bending to occur more anteriorly along the upperand lower frame portions (where the side members are thinner). As aresult, when bending, little to no actual bending or flexing may occurwithin the region of posterior arced regions 216 a, 216 b, as seen inFIGS. 13A-13C. Such a configuration prevents posterior arced regions(also referred to herein as joints) 216 a, 216 b from becomingincreasingly acute, and jabbing into the backwall of the vestibuleduring insertion or use, providing greatly increased comfort.

As seen in FIG. 12A (also particularly apparent in FIGS. 1-5), the upperand lower frame portions of the device may include distinct anteriorcorners, which are defined by a relatively tight radius of curvatureacross bumpers 138, 238, at the corners. For example, the radius ofcurvature across bumpers 138 or 238 may be in a range of about 8 toabout 22 mm, about 10 to about 20 mm, or about 15 mm. The upper andlower frame portions are not simply rounded, e.g., with an oval orcircular configuration, or defined by a generally constant radius ofcurvature over a significant portion of their length. As shown in FIG.12A and FIGS. 1-5, the side members on either side of the upper andlower frame portions may be relatively straight from the thickenedposterior regions 216 towards the forward (anterior) direction, towardsthe relatively tightly curved corners at anterior bumpers 138 or 238.Such tightly curved corners 138, 238 (e.g., they could be termed“squared corners”) conform to the anatomical shape of the upper andlower anterior vestibules between the dental arch, gums and the person'slips. The upper anterior corner bumpers 138, 238 may also angle or flaredownwardly and outwardly across the thickened section, while the loweranterior corner bumpers 138, 238 may similarly angle or flare upwardlyand outwardly. This is perhaps best seen in the corner bumpers of FIGS.2 and 13C. Such configurations ensure that the frame does not contact orirritate the canine prominence of a patient. Such shape and contouringprovides increased comfort to the patient.

Because of anatomical differences in the length of the upper and lowerdental arches and associated vestibules, the two upper corner thickenedbumpers 138, 238 of the upper frame portion may be further apart fromone another as compared to the two lower corner bumpers 138, 238 of thelower frame portion. As described relative to the anterior width of theupper and lower frame portions, the upper frame anterior width 122 maybe greater than the lower frame anterior width 122′ (see FIGS. 1, 2, and6). Where the corner thickened bumpers 138, 238 are positioned at theends of the anterior width (i.e., the intersection between the sidemembers and the corresponding upper or lower anterior connectingmembers), the distance between such corner thickened bumpers alsodiffers from upper to lower, with the upper corner thickened bumpers138, 238 being further apart from one another than the lower cornerthickened bumpers 138, 238. Such a difference anatomically conforms todifferences in sizes of the upper and lower dental arches, and the upperand lower anterior vestibules. This difference may also cause the upperlip to flare out further (in the forward, z-direction) than flaring ofthe lower lip. For example, the upper lip may actually be forward of thelower lip, or the Δz difference provided by the expanded device mayexhibit a greater Δz in the upper lip than the lower lip (i.e.,difference in positions of the upper lip due to the expanded device maybe greater than the difference in lip positions of the lower lip, due tothe expanded device).

Also for anatomical reasons, the upper corner thickened bumpers 138, 238may be more rounded, and enlarged as compared to the two lower cornerthickened bumpers 138, 238. Larger, upper corner bumpers also aids inensuring that the upper lip is flared out further than the lower lip. Asdescribed herein, one or both of the upper or lower corner thickenedbumpers 138, 238 may include a bumper cover (e.g., 238′ of FIGS. 6-9 and11) comprising a material with greater softness, greater flexibility,and/or greater elasticity than the underlying bumpers of the frame. Suchcushioning bumper covers 238′ may provide a comfortable elastic cushionbetween the upper and lower gums and lips. FIGS. 12A-16A do not show anybumper covers, in order to better show the underlying frame geometry,particularly bumpers 238 that such covers may be bonded to or otherwiseattached to.

Device 300 is further shown as including a posterior crossbar 224interconnecting the posterior arced regions 216 of the first and secondupper and lower side members 208 and 210. As described, crossbar 224 maybe configured, in combination with a mandibular ramus, to effectposterior loading of the flexible, resilient frame 202, which posteriorloading assists in flaring the cheeks and lips outward, forward, andopen (i.e., in x, y, and z-axis directions).

As shown in FIG. 12A and described previously, the posterior crossbar224 may include first and second curved members 224 a and 224 b whichare posteriorly curved (i.e., curved backwards), so as to represent themost posteriorly disposed portions of the expansion device (e.g., seethe side views of FIGS. 3 and 8). The posteriorly curved members 224 a,224 b may be joined at essentially a middle portion of the crossbar 224,near anteriorly curved portion 226. Crossbar 224 may thus include threecurves (e.g., two posteriorly curved portions 224 a and 224 b, and ananteriorly curved portion 226 or other middle flexure feature). Becauseof the posterior curvature of members 224 a, 224 b, these posteriorlycurved portions can load against the soft tissue covering mandibularramus of the patient, so that the ramus applies posterior loading to thedevice through crossbar 224, pushing the device 300 forward. Suchposterior loading further flares the lips of the patient forward,increasing the working field available within the mouth, particularlyadjacent the lips. Curved members 224 a, 224 b may also facilitate thecollapsed insertion configuration of the frame, where the frame iscollapsible from side-to-side upon application of a side-to-sidecollapsing force, as well as facilitating the expanded configuration ofthe frame, where the frame is outwardly expanded by opening up fromside-to-side as the collapsing force is released. Posteriorly curvedmembers 224 a, 224 b may also aid in preventing stimulation of the gagreflex of the patient.

Rather than continuous cross-member 227 across the rear of anteriorlycurved portion 226, the configuration of FIG. 12A shows retentionprotrusions 227′, which aid in retaining tongue guard 234 in place,while also allowing its insertion from behind. In addition, by removingthe continuous cross-member 227 (and even with retention protrusions227′), the ease of collapsing the frame from side-to-side is improved.

FIG. 12B illustrates another device 400 also similar to device 200, butwithout the crossbar 224. Even without such a crossbar, the posteriorends 216 have been found by the inventors to provide for at least somedegree of posterior loading of the device as the posterior ends 216 bearagainst the backwall of the vestibule of the patient. FIG. 12Cillustrates another device 500 similar to devices 200, 300, and 400, butin which most of the posterior crossbar 224 has been removed. Device 500instead provides inwardly protruding extensions 546 on posterior arcedregions or joints 216 a, 216 b. Such elongate extensions may besufficient in length (e.g., 0.25 inch to 1 inch in length) to stillprovide posterior loading of extensions 542 on the mandibular ramus ofthe patient, without providing a continuous crossbar between posteriorarced regions 216. Where such extensions are provided, they may berounded at their free ends for comfort. It will be apparent than indevices 400 and 500, no tongue guard may be provided.

In an embodiment, the posterior crossbar 224 may be selectivelyremovable from the remainder of frame 202. For example, the crossbarcould be configured as a tube that fits over projections such asprojections 542 seen in device 500, or a ball and socket joint could beprovided at each end (e.g., at joints 216), or any other suitableconnection mechanism (e.g., press-fit, friction fit, snap fit, etc.)could be provided. If desired, a practitioner could convert theconfiguration seen in FIG. 12A to that of 12B or 12C by simply cuttingor otherwise removing some portion or all of the crossbar 224.

III. Exemplary Methods of Placement and Use

FIGS. 13A-17B illustrate various aspects associated with placement anduse of the cheek and lip expansion devices. For example, FIGS. 13A-13Cshow how the device 300 may be collapsed from top to bottom. FIG. 13Ashows partial collapse as compared to the expanded state seen in FIG.12A, while FIG. 13B shows progressively further top to bottom collapse,and FIG. 13C shows device 300 collapsed top to bottom to the degree thatthe latch member 233 can be engaged with cross-member 231. As shown,(e.g., see FIG. 13B), the cross-member 231 may include a recess formedinto the posterior surface of the cross-member, into which latch member233 is received, latching the upper and lower frame portions 204, 206 toone another.

A comparison of FIG. 12A with FIGS. 13A-13C show how the upper and lowerside members (e.g., 208 a and 210 a on a first side and 208 b and 210 bon a second side) are joined at their posterior ends to form first andsecond bendable radii about arced regions 216, which resist bending at adistinct point so as to spread the bending forces out away from regions216, towards the other portions of the side members 208 and 210. Forexample, because of the thickening 240 at posterior regions 216, littleto no bending may actually occur at this posterior location, while themajority of the bending may occur along the thinnest regions of the sidemembers (e.g., between thickened bumpers 238 and thickened posteriorends 240). Other mechanisms could alternatively be employed to similarlyresist bending at a desired distinct location (e.g., use of a differentmaterial, etc.).

FIG. 13C also perhaps best illustrates how the thickened corner anteriorbumpers 238 of both the upper and lower frame portions may also beanatomically angled, so as to more comfortably fit within the upper andlower corners of the anterior vestibule. Specifically, the lower bumperis shown as angling upward and outward, and the upper bumper as anglingdownward and outward. For example, as labeled on the left side in FIG.13C, the lower corner bumper 238 may include outside and inside angledsurfaces 348 and 350, respectively. Such angles match the anatomy of thecorners of the vestibule into which lower bumper 238 is to be received.Similarly, the upper corner bumper 238 is shown as including outside andinside angled surfaces 352 and 354, respectively, which angles match theanatomy of the corners of the vestibule into which the upper bumper 238is to be received. For example, the lower outside angle 348 may be in arange from about 40° to about 80°, or from about 50° to about 70° (e.g.,about 60°) relative to horizontal (e.g., a horizontal line runningacross the bottom of lower connecting member 214). The lower insideangle 350 may be in a range from about 10° to about 50°, or in a rangefrom about 20° to about 40° (e.g., about 30°) relative to horizontal(e.g., a horizontal line running across the bottom of lower connectingmember 214). The upper outside angle 352 may be in a range from about30° to about 70°, or in a range from about 40° to about 60° (e.g., about50°) relative to horizontal (e.g., a horizontal line running across thebottom of lower connecting member 214). The upper inside angle 354 maybe in a range from about 20° to about 60°, or in a range from about 30°to about 50° (e.g., about 40°) relative to horizontal (e.g., ahorizontal line running across the bottom of lower connecting member214). In an embodiment the lower and upper outside angles 348 and 352may be approximately equal (and in opposite directions), being angledtowards one another, as shown. In another embodiment, the angles maydiffer (e.g., upper greater than lower, or lower greater than upper).These angulated upper and lower thickened corner bumpers 238 extendoutwardly, towards the bony structure bounding the vestibule. Similaranatomical angulation may be provided on the right side upper and lowerbumpers 238.

In addition to this collapsibility in a top to bottom dimension, thedevice may also be configured as described above, to collapseside-to-side. FIGS. 14A and 14B illustrate how a practitioner maycollapse the device side-to-side, due to the flexible, spring-likecharacteristics of the frame 202. Where no crossbar is present (e.g.,see FIG. 12B), the posterior ends 216 may be pressed towards oneanother, to collapse the device in a side-to-side dimension. Even wherea crossbar 224 is present, as seen in FIG. 12A and FIGS. 14A-14B, thecrossbar 224 may include an anteriorly curved central portion 226, whichfacilitates side-to-side collapse as the posterior ends of the deviceare pushed towards one another. The two posteriorly curved portions 224a and 224 b may also facilitate side-to-side collapse. During collapse,the curved portion 226 advances forwardly, e.g., and may pass over orunder lower anterior connecting member 214, depending on the degree ofside-to-side collapse. Posteriorly curved members 224 a and 224 b mayalso move closer together, accommodating the collapse, as seen in FIGS.14A and 14B. As seen in FIG. 14A, as posterior arced regions 216 arepressed towards one another, the ends of curved members 224 a, 224 badjacent central curve 226 may become increasingly parallel to oneanother, and then possibly eventually touching, as seen in FIG. 14B,depending on the degree of side-to-side collapse. Such a top to bottomand side-to-side collapsed configuration as seen in FIGS. 14A or 14B isparticularly compact, making it quite easy to insert into a patient'smouth without requiring the patient to open their mouth to anuncomfortable degree.

FIGS. 15A-15B illustrate one exemplary method of insertion, while FIG.16A illustrates another method. As shown in FIG. 15A, the practitionermay collapse the expansion device 300 top to bottom, while employinglittle if any of the side-to-side collapsibility of the expansiondevice. Rather, the practitioner may wish to insert one posterior arcedregion 216 of the expansion device 300 into one side of the mouthfollowed by shoehorning the other posterior arced region 216 into themouth. Because the device is collapsed top to bottom during suchinsertion, the patient is not required to open their mouth to anuncomfortable degree, but may simply insert one posterior region (e.g.,216 a) towards the rear of the vestibule or oral cavity, and then swingthe other posterior region (e.g., 216 b) into place, towards theopposite vestibule. If desired, while swinging the second posterior endinto place, some of the device's side-to-side collapsibility may beemployed, should the practitioner simply compress the two posterior ends216 towards one another.

FIG. 16A illustrates another method of insertion, where no suchshoehorning of one posterior side and then the other may be employed,but where the expansion device is collapsed top to bottom (e.g., andlatched in that collapsed state), and then also collapsed side-to-sideas seen in FIGS. 14A and 14B. By employing the latch, such may easily beachieved with a single hand. The width of the expansion device is sosmall when so collapsed, that it easily fits into the mouth of apatient, without requiring them to open their mouth to an uncomfortabledegree. By way of example, the top to bottom collapse may reduce theheight of the device from about 85-100 mm (expanded) to about 30 mm(e.g., a reduction of 50% or more, or 60% or more (e.g., about 50% toabout 70%)). The side-to-side collapse may reduce the width of thedevice from about 100 mm (expanded) to about 60-70 mm (e.g., a reductionof about 30% to about 40%). As will be apparent the majority (perhapsnearly all) of the side-to-side collapse occurs posteriorly, making theposterior collapsed width similar to that of the anterior widths 122 and122′ described in conjunction with FIGS. 1 and 6. Such decreased heightand width allows the multi-dimensionally collapsed expansion device toeasily be inserted into the mouth of the patient, as seen in FIG. 16A.No uncomfortable opening of the mouth, or uncomfortable side-to-sidestretching of the lips is needed.

In either case, once inserted and expanded, the expansion device“floats” within the patient's mouth, with the side members 208, 210 ofthe upper and lower frame portions 204 and 206 resting in the upper andlower vestibules of the patient, between the alveolar ridge and the lipsor cheeks. The posterior crossbar 224 (if present) crosses from one sideof the dental arches to the other, in a retromolar region, behind themolars of the patient. As described above, the crossbar 224 may bearagainst the soft tissue covering the mandibular ramus R of the patient,exerting a forward force on the device, pushing it forward. FIGS.16B-18D show how the soft tissue covering the mandibular ramus R isabutted by the posteriorly curved portions of crossbar 224, providingthe desired posterior loading. Such posterior loading further flares theupper lips forward (in the z-dimension) and upward (in the y-dimension)and the cheeks outward (in the x-dimension). The lower lips aresimilarly further flared forward, (in the z-dimension), downward (in they-dimension), with the cheeks being flared outward (in the x-dimension).Such posterior loading thus widens the working field. Only the lipprotecting members of the expansion device may reside outside of themouth (over the center of the upper and lower lips), with the otherportions of the frame being received within the mouth. Side members 208and 210 may be received within the upper and lower facial vestibules,and the upper and lower anterior connecting members may be receivedwithin the upper and lower anterior vestibules. No portion interfereswith access to the dental arches. If a posterior crossbar is present,the crossbar 224 passes retromolarly, between the posterior teeth andthe ramus.

FIGS. 16B and 16C illustrate how when positioned within the person'smouth, the patient still has full movement of their jaw, so as to allowthe user to open and close their jaw as normally possible. FIG. 16Bshows the jaw open, with FIG. 16C showing the jaw closed. No portion ofthe frame interferes with this ability to fully open and fully close thejaw, while the expansion device is in the mouth. As seen in FIG. 16C,the expansion device holds the lips comfortably retracted or expandedfrom the dental arches, so that the teeth of both arches are easily andfully visible, even with the jaw closed. As seen, the frame inflates,displaces, and flares the patient's cheeks and lips away from the teeth,so that no contact is made between the frame and the teeth or gums. Theframe may be devoid of any structures that would obstruct access to theteeth when the frame is expanded, and that would prevent the patientfrom fully biting down and making full occlusal contact between theperson's upper and lower teeth. For example, the frame may be devoid ofany structures interconnecting the upper and lower frame portions apartfrom the posterior crossbar, so as to not impede access to the person'steeth and gums when the frame is expanded in the mouth. The posteriorcrossbar 224 does not impede access, as it passes across the retromolarregion, so as to not interfere with the 2^(nd) or even the 3^(rd)molars, if present. In addition, no anterior ring is present thatcircles the perimeter of the patient's mouth opening, whichuncomfortably stretches the lips side-to-side, and which can interferewith access to certain teeth (e.g., canines and bicuspids, as it passesfrom the upper to lower portions of the oral cavity).

The frame may be flexible when expanded in the mouth so as to permit alltypical functional movements of the person's mandible in x-axis(side-to-side), y-axis (up and down), and z-axis directions (forward andbackward). In other words, the person is able to close the mandible(generally a y-axis movement), as well as move the mandible in any othertypical motion possible when the frame is not expanded within the mouth.The frame simply floats within the vestibule portion of the mouth,between the cheeks/lips and the dental arch (teeth and gums in thealveolar ridge), inflating the cheeks and lips outwardly and forwardly,but permits normal movement and functioning of the jaw when expandedwithin the mouth. Of course, the cheeks and lips are held outward andforward, inflated away from their normal positions when a mouth isclosed with no such device inserted.

In an embodiment, the frame does not fully stretch the lips side-to-sidearound the person's mouth, to their limits, but rather holds them open,and flares them forward, to a comfortable degree, all while providing awidened working field for the practitioner. In other words, the frameinflates and flares the lips forwardly and away from the anterior teethin a z-axis direction without fully stretching the lips side-to-side inan x-axis direction. This permits the persons lips and cheeks to beasymmetrically deformed, facilitating enlargement of the working fieldon a particular side of the mouth. For example, many existing retractiondevices grab the lips on opposite sides of the mouth, pulling them apartside-to-side. As seen in FIGS. 17A and 17B, the present devices do notso stretch the lips, but allow further expansion of one side or theother. In other words, Because of the comfortable expansion of the lipsand cheeks that is instead provided, the practitioner can reach into themouth and pull the lips to one side or the other, expanding one side orthe other side asymmetrically, as seen in FIGS. 17A-17B. This permitsasymmetric deformation of the lips to either side, facilitating furtherenlargement of the working field on a particular side of the mouth. Inaddition, while so doing, as the expansion device itself “floats” withinthe mouth, such movements or expansions by the practitioner generallydoes not move the device, which remains generally in the same positionin the mouth.

As will be apparent from the described methods and from FIGS. 13A-17B,the flexible spring-like frame provides an insertion configurationwherein the frame is inwardly collapsible in multiple dimensions, e.g.,at least from top to bottom, and from side-to-side. During such collapsein two dimensions, some collapse in the third dimension (z-axis—forwardto back) may also occur. The flexible spring-like frame also provides asecond, expanded configuration, where the frame is outwardly expandableby opening up from top to bottom and from side-to-side. The expandedconfiguration provides retraction of a person's cheeks and lips tocreate an enlarged working field that permits unobstructed access toboth upper and lower dental arches, including all teeth from the secondmolar position forward. The upper frame portion 204 of the frame isconfigured to extend continuously about the upper dental arch, from afirst posterior arced region (e.g., 216 a) that is behind a second molarposition on one side of the upper dental arch to a second posteriorarced region (e.g., 216 b) that is behind a second molar position on anopposite side of the upper dental arch. The lower frame portion 206 isconfigured to continuously extend about the lower dental arch, from thefirst posterior arced region (e.g., 216 a) that is also behind thesecond molar position on one side of the lower dental arch to the secondposterior arced region (e.g., 216 b) that is also behind the secondmolar on the opposite side of the lower dental arch. The first andsecond posterior regions 216 join the upper and lower frame portions204, 206 to one another, and provide a bendable radius on either side(e.g., about arced region 216 a, along side members 208 a, 210 a, andabout end 216 b, along side members 208 b, 210 b) that facilitates theinsertion configuration, where the frame is inwardly collapsible fromtop to bottom, as well as the expanded configuration, where the frame isoutwardly expanded by opening from top to bottom. The posterior arcedregions 216 may also be collapsed side-to-side, towards one another,facilitating side-to-side collapse of the frame, and its subsequentexpansion upon release of the collapsing force. The posterior regions216 may be thickened in the vicinity of the frame where such ends arelocated, so as to better resist bending at that particular point,distributing the bending forces along a greater length on either side ofthe arced region, into the side members. Such thickened regions 240 alsohelp to open the frame upward, (i.e., top to bottom), creating increasedresistance to closing of the jaw-like frame. The frame components,particularly the side members 208, 210, thus include relatively thinnercross-sections through essentially the middle portion of each sidemember of the upper and lower frame portions, causing much of thebending to occur within these thinner frame structures.

The shape of the side members 208, 210, upper and lower anteriorconnecting members 212, 214, and the frame 202 in general, may beconfigured to follow the contours of the portions of the vestibule intowhich any given particular portion is to be received. For example, theside members 208, 210 of the upper and lower frame portions may becurved and shaped anatomically, for receipt into the facial vestibule oneither side of the dental arches. Similarly, the anterior corner bumpers238 at the anterior ends of each side member may be shaped, curved, andsized for receipt into the corners of the anterior portions of the upperand lower vestibules, at the front of the dental arches. Because ofdifferences in the upper and lower dental arches, and in the upper andlower vestibules associated with such arches, the upper and lower frameportions may be differently sized and shaped. For example, the lowerframe 206 may be overall shorter, and narrower at its anterior frontwidth, while the upper frame portion 208 is overall longer, and wider atits anterior front width. The side members 208 of the upper frameportion may be shorter than the side members 210 of the lower frameportion, and the thickened anterior corner bumpers 238 of the upperframe may be more rounded, and larger than those of the lower frameportion. All such differences better accommodate the actual anatomy ofthe person, providing better comfort when the frame is expanded withinthe vestibules.

The upper and lower frame portions (particular the side members of each)expand the upper and lower facial vestibules (e.g., adjacent the cheeks)laterally (side-to-side—in the x direction), flaring the cheeksoutwardly as the frame resides within the vestibule, expanding andflaring the cheeks outward, like a tent. The upper and lower anteriorvestibules are similarly expanded, but in a forward direction (in thez-direction), flaring the lips forward. The upper and lower anteriorvestibules are also expanded in the y-direction, retracting the upperlips upwardly and the lower lips downwardly In other words, the cheeksare expanded in the x-direction, while the lips are generally expandedin the z and y directions.

FIGS. 18A-18D illustrate how the tongue guard 234 may gently house thetongue, so as to reduce its interference with the practitioner's workingfield, protecting the tongue from injury, but at the same time allowingthe patient to move the tongue up, down, or to either side. The tongueguard may hold and guide the person's tongue, but may not significantlypush the tongue back, flatten the tongue, or thicken the tongue.Flattening or thickening the tongue (by pushing it down or back) mayincrease risk of injury, as it increases the surface area of the tongueas a target for a drill or other dental tool. Many other existing tongueguard devices tend to forcefully push the tongue back, flatten thetongue, or thicken the tongue, which can be uncomfortable to thepatient, while also increasing injury risk. The tongue guard may holdthe tongue in place, even if the jaw is closed, a characteristic whichalso differs from many existing retraction devices. For example, FIGS.18A-18D shows how the patient may move the distal tip of the tonguewithin tongue guard 234 to the right (FIG. 18A), to the left (FIG. 18B),up (FIG. 18C) or down (FIG. 18D). Tongue guard 234 holds and guides thedistal tip of the tongue, while still permitting such movement by thepatient. The tongue is not significantly flattened or thickened,particularly the exposed portions thereof.

As used in this specification and the appended claims, the singularforms “a,” “an” and “the” include plural referents unless the contextclearly dictates otherwise.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. A frame of a cheek and lip expansion deviceconfigured to extend about dental arches of a user, the framecomprising: an upper frame portion including a first upper side member,a second upper side member, and an upper anterior connecting member thatjoins the first upper side member and the second upper side member atanterior regions of the first upper side member and the second upperside member; a lower frame portion including first lower side member, asecond lower side member, and an lower anterior connecting member thatjoins the first lower side member and the second lower side member atanterior regions of the first lower side member and the second lowerside member; a first thickened structure positioned at a first posteriorregion of a frame, the first thickened structure being connected to thefirst lower side member and the first upper side member and having anenlarged cross-section relative to adjacent portions of the first lowerside member and the first upper side member; and a second thickenedstructure positioned at a second posterior region of the frame that issubstantially opposite the first posterior region, the second thickenedstructure being connected to the second lower side member and the secondupper side member and having an enlarged cross-section relative toadjacent portions of the second lower side member and the second upperside member, wherein: the frame is configurable in a collapsedarrangement in which the lower anterior connecting member is benttowards the upper anterior connecting member responsive to imposition ofa flexing force; the first and the second thickened structures areresistant to bending; and in the collapsed arrangement, the flexingforce is substantially transferred from the first and the secondthickened structures to the adjacent portions of the first and secondlower side members and the first and second upper side members.
 2. Theframe of claim 1, wherein: the first upper side member, the first lowerside members, and the first thickened structure form a first bendableradius; and the second upper side member, the second lower side members,and the second thickened structure form a second bendable radius.
 3. Theframe of claim 1, further comprising a posterior crossbar that connectsthe first thickened structure to the second thickened structure.
 4. Theframe of claim 3, wherein: the posterior crossbar comprises a first anda second posteriorly curved members; and a middle portion of theposterior crossbar are anteriorly curved to facilitate inward collapseof the frame from side-to-side as the first thickened structure and thesecond thickened structure posterior are pressed towards one another. 5.The frame of claim 1, wherein the upper anterior connecting memberincludes a greater anterior width than an anterior width of the loweranterior connecting member.
 6. The frame of claim 1, further comprising:two upper corner thickened bumpers positioned on the upper frameportion; and two lower corner thickened bumpers positioned on the lowerframe portion, wherein the two upper corner bumpers are further apartfrom one another than the two lower corner bumpers.
 7. The frame ofclaim 6, wherein: the upper corner thickened bumpers are rounded andenlarged as compared to adjacent portions of the upper frame portion;and the lower corner thickened bumpers are rounded and enlarged ascompared to adjacent portions of the lower frame portion.
 8. The frameof claim 6, wherein the upper and lower corner thickened bumpers arecomprised of an elastomeric material disposed over the upper frameportion and lower frame portion, respectively.
 9. A cheek and lipexpansion device, the device comprising: a first thickened structurepositioned at a first posterior region of a frame, the first thickenedstructure having an enlarged cross-section relative to adjacent frameportions; a second thickened structure positioned at a second posteriorregion of the frame that is substantially opposite the first posteriorregion, the second thickened structure having an enlarged cross-sectionrelative to adjacent frame portions; an first frame portion that extendsfrom the first thickened structure to the second thickened structure,the first frame portion being configured to extend about an upper dentalarch of a user and including a first subset of the adjacent frameportions; and a second frame portion that extends from the firstthickened structure to the second thickened structure, the second frameportion being configured to extend about an lower dental arch of theuser and including a second subset of the adjacent frame portions,wherein: the frame is configurable in a collapsed arrangement in whichan anterior portion of the first frame portion is bent towards ananterior portion of the second frame portion responsive to imposition ofa flexing force; the frame is further configurable in an expandedarrangement responsive to removal of the flexing force; the first andthe second thickened structures are resistant to bending; and in thecollapsed arrangement, the flexing force is substantially transferredfrom the first and the second thickened structures to the adjacent frameportions such that the adjacent frame portions flex.
 10. The device ofclaim 9, wherein: the first frame portion includes a first upper sidemember, a second upper side member, and an upper anterior connectingmember that joins the first upper side member and the second upper sidemember at anterior regions of the first upper side member and the secondupper side member; the second frame portion includes first lower sidemember, a second lower side member, and an lower anterior connectingmember that joins the first lower side member and the second lower sidemember at anterior regions of the first lower side member and the secondlower side member; the first thickened structure is connected to aposterior portion of the second lower side member and a posteriorportion of the second upper side member; and the second thickenedstructure is connected a posterior portion of the second lower sidemember and a posterior portion of the second upper side member.
 11. Thedevice of claim 10, wherein the upper anterior connecting memberincludes a greater anterior width than an anterior width of the loweranterior connecting member.
 12. The device of claim 10, furthercomprising a posterior crossbar that connects the first thickenedstructure to the second thickened structure, wherein: the posteriorcrossbar comprises a first and a second posteriorly curved members; anda middle portion of the posterior crossbar are curved to facilitateinward collapse of the frame from side-to-side as the first thickenedstructure and the second thickened structure posterior are pressedtowards one another.
 13. The device of claim 12, wherein the frame isdevoid of any structures interconnecting the upper and lower frameportions apart from the posterior crossbar.
 14. The device of claim 10,further comprising: two upper corner thickened bumpers positioned on thefirst frame portion; and two lower corner thickened bumpers positionedon the lower frame portion, wherein the upper and lower corner thickenedbumpers are comprised of an elastomeric material disposed over the firstframe portion and lower frame portion, respectively.
 15. The device ofclaim 14, wherein: one of the two upper thickened bumpers is positionedbetween the first upper side member and the upper anterior connectingmember; another of the two upper thickened bumpers is positioned betweenthe second upper side member and the upper anterior connecting member;one of the two lower thickened bumpers is positioned between the firstlower side member and the lower anterior connecting member; and anotherof the two lower thickened bumpers is positioned between the secondlower side member and the lower anterior connecting member.
 16. Thedevice of claim 14, wherein the two upper corner bumpers are furtherapart from one another than the two lower corner bumpers.
 17. The deviceof claim 14, wherein: the upper corner thickened bumpers are rounded andenlarged as compared to adjacent portions of the upper frame portion;and the lower corner thickened bumpers are rounded and enlarged ascompared to adjacent portions of the lower frame portion.
 18. A frame ofa cheek and lip expansion device, the frame comprising: a firstthickened structure positioned at a first posterior region of the frame,the first thickened structure having an enlarged cross-section relativeto adjacent frame portions; a second thickened structure positioned at asecond posterior region of the frame that is substantially opposite thefirst posterior region, the second thickened structure having anenlarged cross-section relative to adjacent frame portions; an firstframe portion that extends from the first thickened structure to thesecond thickened structure, the first frame portion being configured toextend about an upper dental arch of a user and including a first subsetof the adjacent frame portions; and a second frame portion that extendsfrom the first thickened structure to the second thickened structure,the second frame portion being configured to extend about an lowerdental arch of the user and including a second subset of the adjacentframe portions, wherein: the first and the second thickened structuresare resistant to bending; and the first and the second thickenedstructures are configured to transfer a flexing force acting to pressthe first frame portion towards the second frame portion to the adjacentframe portions.
 19. The frame of claim 18, wherein: the first frameportion and the second frame portion are configurable in a collapsedarrangement in which an anterior portion of the first frame portion isbent towards an anterior portion of the second frame portion responsiveto imposition of the flexing force; the first frame portion and thesecond frame portion are further configurable in an expanded arrangementresponsive to removal of the flexing force; and in the collapsedarrangement, the flexing force is substantially transferred from to theadjacent frame portions such that the adjacent frame portions flex. 20.The frame of claim 18, further comprising a posterior crossbar thatconnects the first thickened structure to the second thickenedstructure, wherein: the posterior crossbar is configured for inwardcollapse from side-to-side as the first thickened structure and thesecond thickened structure are pressed towards one another; and theframe is devoid of any structures interconnecting the first and thesecond frame portions apart from the posterior crossbar.